The present invention pertains to a McPherson strut bearing for the upper connection of a McPherson strut in a motor vehicle.
McPherson strut bearings of prior-art designs are used to keep the vibrations generated on the wheel suspension of a motor vehicle away from the body.
The upper ends of the McPherson struts connected to the McPherson strut bearing are accommodated mostly in a damping spring, which is supported on the lower outer circumference of the McPherson strut bearing. This type of wheel suspension has been known as the McPherson principle.
Such a suspension mounting with a McPherson strut bearing is described, e.g., in DE 43 26 197 A1. The solution disclosed in the said document contains a McPherson strut bearing with a metallic inner part, in which a central through hole is present for mounting the upper end of the McPherson strut. A circular elastomer body is injection-molded on the outer circumference of the metallic inner part. The metallic inner part is accommodated together with this surrounding elastomer body in an elastic bearing body. The entire McPherson strut bearing is then inserted into a metallic housing, which can be fixed on the body of the motor vehicle. The vibrations of the wheel suspension which can be transmitted to the McPherson strut bearing via the end of the McPherson strut as well as via the spring, which is in contact with the underside of the McPherson strut bearing, are damped in the existing elastomer bodies, so that, on the whole, an uncoupling of the vibrations is achieved.
However, it is disadvantageous in such a design of the McPherson strut bearing that especially movements of this McPherson strut bearing extending at right angles to the longitudinal direction of the McPherson strut are hardly damped at all. Furthermore, the elastic bearing body is accommodated directly in a metallic housing and it correspondingly has no freedom of movement. Even though the design of the McPherson strut bearing being described is very simple, it does not sufficiently meet increased requirements in terms of comfort as a consequence of its relatively hard spring characteristics.
A McPherson strut bearing for the upper connection of a McPherson strut in a motor vehicle, which has an inner part with a central through hole for accommodating the upper end of the McPherson strut, has been known from U.S. Pat. No. 4,478,396. An elastomer body is arranged circularly on the outer circumference of the inner part; this elastomer body is split approximately in the middle according to the disclosure of this document.
The basic technical object of the present invention is to develop a McPherson strut bearing for the upper connection of a McPherson strut in a motor vehicle, in which the uncoupling of the vibrations generated on the wheel suspension against the vehicle body also meets high requirements in terms of comfort. The McPherson strut bearing shall have a simple design and be able to be manufactured at low cost, so that it can be manufactured in the smallest possible number of assembly steps. An assembly process for such a McPherson strut bearing shall correspondingly be developed as well.
This technical object is accomplished by the present invention with the features of patent claim 1 as well as the process features according to patent claim 17.
Thus, a McPherson strut bearing according to the present invention for the upper connection of a McPherson strut in a motor vehicle has an inner part with a central through hole for accommodating the upper end of a McPherson strut. An elastomer body is arranged circularly on the outer circumference of the inner part. Moreover, the inner part with the elastomer body is accommodated within an elastic bearing body. However, unlike in the solutions known from the state of the art, a cage is provided between the inner part with the elastomer body made in one piece with it and the elastic bearing body. This [cage] completely accommodates the inner part together with the elastomer body. The cage is in turn accommodated completely in the elastic bearing body up to a bilateral opening cross section for introducing and fastening the upper end of the McPherson strut.
At least the cage of the bearing bodies and a circlip surrounding the bearing body at least partially are split in a plane passing through the central longitudinal axis of the McPherson strut bearing.
Such a McPherson strut bearing design is very simple, can be manufactured at low cost and is inserted as a prefabricated assembly unit directly into the motor vehicle and is subsequently connected to the McPherson strut and the motor vehicle body.
Other embodiments of the present invention are the subject of the subclaims.
It is proposed, e.g., that a flange be made in one piece with the outer surface of the elastic bearing body. This flange advantageously comprises two webs, between which a circlip is inserted.
For reasons of stability, the inner part should be designed as a metallic inner part of an approximately disk-shaped geometry, wherein the circumferential edge area of the metallic inner part may be bead-shaped or it forms a bead. The bead-shaped design facilitates the fastening of the elastomer body, which is preferably arranged on it by injection molding. This very small, prefabricated unit of a McPherson strut bearing according to the present invention also makes it possible to prepare contact surfaces on the elastomer body during the manufacturing process for receiving and guiding the McPherson strut to support its fastening or mounting in the motor vehicle. Furthermore, the elastomer body can contribute to an increase in comfort due to its shape by damping buffers being made in one piece with the elastomer body on at least one side in another embodiment of the present invention. These damping buffers may have various geometries.
Provisions are made in another, highly advantageous embodiment of the present invention for composing the cage, the bearing body and the retaining ring from two centrally divided individual parts of identical design. The McPherson strut bearing according to the present invention is substantially simplified by this measure. In addition, the number of individual parts is reduced, on the whole, which leads to considerable advantages in terms of costs.
The circlip, which is used, on the whole, to hold together a McPherson strut bearing according to the present invention as a prefabricated assembly unit, also has one peculiarity: It can be manufactured from two congruent circlip halves. These circlip halves have a connection pin on one side and a mount, which is complementary hereto, on the opposite side of the circlip half, so that the two circlip halves can be coupled with one another. However, only one circlip half must be manufactured in duplicate.
According to another embodiment of the present invention, each of the cage half shells formed by the division shall, moreover, have an adjusting pin on its cage jacket circumference, which pin can be introduced into a complementary adjusting groove of the associated other cage half shell. Since the cage half shells are of identical design according to the present invention, each cage half shell has both an adjusting groove and an adjusting pin. These are preferably arranged on the cage jacket circumference. Before the mounting of the elastomer body with the inner part arranged therein, the cage half shells formed by the division form a state of preassembly, which is characterized by an enlarged, e.g., slightly conical opening cross section. The elastomer body with the inner part arranged within the said elastomer body can be inserted into the cage in a simple manner through this enlarged opening cross section without having to overcome a considerable resistance. The components can thus be easily assembled. The entire assembly unit is subsequently held together by a retaining ring placed on the cage jacket circumference and thus secured.
Furthermore, it is considered to be meaningful in a McPherson strut bearing according to the present invention to provide, e.g., the bearing body with an inner contour complementary to the outer contour of the cage. To meet the increased requirements in terms of comfort, it is, moreover, possible to make damping buffers in one piece with the outer contour of the elastomer body and/or of the bearing body.
Furthermore, the underside of the bearing body should have a geometry that is adapted to the spring plate that is in contact with it.
The following advantageous sequence of assembly of a preferred McPherson strut bearing according to the present invention is obtained in the knowledge of the above-described technical features of a McPherson strut bearing according to the present invention:
Insertion of the inner part jacketed with the elastomer body into the cage half shells of the cage,
fitting together of the cage half shells,
pushing of the retaining ring over the circumference of the cage jacket,
axial deformation of the upper side as well as the underside of the cage, so that the elastomer body is accommodated in the cage with axial pretension,
attachment of the half shells of the bearing body to the outer surface of the cage, and
insertion of the circlip into the mounting groove formed by the webs of the flange, simultaneously connecting the two circlip halves.
The above-mentioned features, which will be explained later, may be used not only alone but also in any desired combination with one another or with prior-art features known from the prior art without going beyond the scope of the present invention.
A preferred exemplary embodiment of a McPherson strut bearing according to the present invention will be explained in greater detail below with reference to the corresponding drawings.